High performance relays are utilized in great numbers in the aircraft, aerospace, and electronics industries in which a premium is placed on minimum weight and physical size for operation under extreme environmental conditions and with high electrical capacities. Relays capable of switching current of 10 amperes or more at switching times of less than a millisecond and occupying total volume of less than seven cubic centimeters make the design and manufacture of the relay parts extremely critical and expensive. In attempting to scale down the size of component parts to reduce the weight and size of the relay, careful attention must be given to strengths of materials in order to withstand shocks of up to 200 g's, vibrations of up to 50 g's, and at the same time the relay must provide minimum contact resistance, as well as sufficient insulation and spacing to prevent voltage breakdown and arcing.
One area of design which has presented problems in achieving a satisfactory relay design is in the mounting of the moving contacts on the armature which is actuated by the electromagnet of the relay. The moving contacts must be firmly supported to maintain high contact pressure with minimum chatter or bounce. The contacts must be insulated from the actuating armature in a manner to withstand breakdown under voltage gradients of 1500 volts or more. At the same time, the mounting arrangement must occupy a minimum of space and yet be rugged, foolproof, easy to assemble.
In the past, movable contacts have been mounted on the armature by various means such as rivets or other fastening devices. These tend to loosen or fail in use and present design and assembly problems. A mounting arrangement is shown in U.S. Pat. No. 3,484,729, assigned to the same assignee as the present invention in which an insulating contact carrier is clamped to the armature by the pivot shaft. The arrangement permits assembly without the use of rivets or the like. However, such an arrangement has been found unsuitable for extremely small relays with reduced electrical clearances between parts.